100% some of the time?

Is giving 100% some of the time good enough?

Let's say I am at the mall and go into the first store. I am 100% Christ-like to the store clerk. I wander around picking up items I may want; have a casual, light-hearted, conversation with her; maybe pick something up off the floor and put it back; decide I don't want an item that is in my arms so I walk back to where I found it and put it where it belongs. She happens to notice and thanks me for doing that as most people would just set it anywhere. Alright, so maybe she didn't know I was a Christian by doing that, but that's not the point. The point is, when I left, she had an improved perception of me (and possibly others my age).

So I finish in that store and move on to the next. I walk in and shop around a little, causing noone any harm, just doing what I need to do. As I'm leaving, I bring the shopping cart to the general area they belong, take out my bags and leave. I didn't necessarily do anything wrong, but as I was walking away from the cart, a woman looked at me and I realized I could have just taken one extra step and pushed the cart in the same direction as the others and stacked it.

Now I was still thinking in my mind how good it felt that I did one simple little thing at the first store, it helped someone out, and they noticed... I gave 100% in the first situation but maybe only 50% in the second. The first store clerk thought highly of me because of my action and possibly thought I did that all the time, everywhere. The second lady could have thought of me as careless and maybe it even strengthened a view she had of all young people being careless.

My point being, to the second woman, I may as well have never done a good act in my life. She knows nothing about me. Both women were strangers and I will probably never interact with either of them again, but by one simple thing in each circumstance, they gained a perception of me. To the second woman's perception, it did me absolutely no good that I had just went above and beyond 15 minutes previously. Sometimes, in my mind, I tell myself that the good an outweigh the bad. That's probably not Biblical and certainly not true when it comes to strangers... so why should that be my idea in my normal everyday life, with my friends and people I come in contact with regularly. I can't justify being crabby to someone by telling myself that I'm USUALLY nice to them. It can't work that way, something's wrong with that.

God, please search my heart, find if there is any wicked way in me and don't let me justify it.